Experimental and longitudinal studies have found that older individuals with more negative age beliefs demonstrate worse health outcomes. The mechanism that explains this process is not known. The overall aim of the proposed project is to investigate for the first time whether stress biomarkers over time reflect a biological process tha links negative age beliefs (defined as disparaging perceptions that are assimilated from society about older individuals as a category) with worse health of older individuals. The importance of examining stress biomarkers as the potential mechanism is enhanced by their potential ability to provide a previously unexamined explanation for racial and gender disparities in aging health. The proposed project will draw on two ongoing complementary longitudinal datasets that focus on community-dwelling older individuals. Thus, we will pursue the following aims and hypotheses for the first time: Aim 1: Examine whether older individuals' age beliefs are associated with stress biomarkers over time. Hypothesis 1: Older individuals' negative age beliefs will predict elevated stress biomarkers over time. Aim 2: Examine whether racial and gender disparities exist in the influence of older individuals' age beliefs on stress biomarkers over time. Hypothesis 2a: Older African Americans will be more vulnerable than same-aged older whites to the adverse impact of negative age beliefs on stress biomarkers over time. Hypothesis 2b: Older women will be more vulnerable than same-aged older men to the adverse impact of negative age beliefs on stress biomarkers over time. Aim 3: Examine whether older individuals' stress biomarkers over time mediate the relationship between age beliefs and worse cognitive and physical health over time. Hypothesis 3: Older individuals' stress biomarkers will mediate the relationship between negative age beliefs and worse cognitive health (i.e., memory deficits, risk of mild cognitive impairment and Alzheimer's disease, and smaller hippocampal volume) and worse physical health (i.e., physical-function deficits, risk of cardiovascular events, and higher mortality) over time. Aim 4: Identify the factors that moderate negative age beliefs' influence on older individuals' stress biomarkers over time. Hypothesis 4: Resiliency factors (i.e. Feeling Useful to Others, Openness, and Emotional Stability) and vulnerability factors (i.e., Age-belief Self-relevance and Adverse Life Events) will moderate negative age beliefs' effect on stress biomarkers over time. This study could identify a new and potentially modifiable process, negative age beliefs' association with stress biomarkers over time, as a factor that contributes to adverse health outcomes among older individuals.